This invention relates to fluid sealing systems of the type in which one or more fluid conduits are extended into associated fluid ports of a fluid housing in which rupture membrane seals are accommodated to serve initially as shipping plugs but which rupture upon the insertion of the conduits to provide fluid communication between conduits and ports while sealing about the conduits.
A typical motor vehicle hydraulic power steering gear includes a housing adapted for rigid attachment to a motor vehicle body, a fluid inlet port in the housing for a high pressure fluid conduit from a pump on the vehicle body, and a fluid discharge port for a low pressure fluid conduit from a reservoir on the vehicle body. Commonly, the steering gear housing is filled with hydraulic fluid at the site where the steering gear is manufactured to reduce the number of tasks which must be performed later when the steering gear is mounted on the vehicle body and the high and low pressure fluid conduits are connected to the inlet and discharge ports. To retain the hydraulic fluid in the steering gear housing, the fluid inlet and discharge ports are sealed closed by removable plastic plugs.
A breakaway seal manufactured by Acadia Polymers, Roanoke, Va., and described in xe2x80x9cBreakaway Sealxe2x80x9d, Machine Design, Sep. 12, 1996, page 40, seals closed a fluid port in a motor vehicle automatic transmission case to prevent escape of fluid in the interval between manufacture of the automatic transmission and installation of the latter on a motor vehicle. The breakaway seal includes a metal carrier interference fitted in the fluid port, a tubular elastomeric gasket attached to the metal carrier, and an integral membrane perpendicular to a cylindrical inside wall of the tubular gasket. The integral membrane includes a plurality of radially oriented ribs, a plurality of relatively thin webs between the ribs, and a stiffener rib. When a distal end of a fluid conduit is thrust into the cylindrical inside wall of the tubular gasket, it ruptures the membrane to open the fluid port. At the same time, the cylindrical inside wall of the tubular gasket seals against a cylindrical outside wall of the fluid conduit to prevent escape of fluid between the gasket and the fluid conduit. While such a breakaway seal may function successfully in a motor vehicle transmission environment, it has not proven successful for sealing closed the fluid inlet and discharge ports in a motor vehicle hydraulic power steering gear housing. Specifically, because of dimensional changes necessary for application in a relatively space-restricted power steering gear housing environment, the xe2x80x9cbreakingxe2x80x9d or rupture pattern of the integral membrane of the aforesaid breakaway seal causes inconsistent rupturing of the integral membrane and unpredictable insertion forces which sometimes are too great for easy manual connection of the high and low pressure fluid conduits to the inlet and discharge ports in the steering gear housing.
FIGS. 1a, 1b and 1c illustrate another prior art rupture seal in which a seal body is molded to an outer metal carrier. The mouth of the seal body is fully exposed to an inserted fluid conduit such that the carrier does not extend over the end face of the seal body. The membrane has a C-shaped tear line defining an inner tear flap inboard of the tear line and a hinge extending between spaced ends of the tear line connecting the tear flap to the membrane. The tear line comprises a thinned, rupturable section of the membrane. One drawback with this design is that the ends of the tear line are susceptible to tear propagation into the hinge region which could cause separation of the tear flap from the membrane. It is also difficult to control the insertion force necessary to rupture the C-shaped tear line, and a conduit must be extended a considerable distance into the port against the membrane before tearing begins which, in some applications, presents a problem where there is limited depth of the ports to receive the conduits.
Another consideration in such fluid sealing systems is the arrangement and presentation of the fluid conduits in applications where more than one fluid conduit is involved. The power steering pump application described above has a fluid supply conduit and a fluid return conduit. The conduits plug into fluid inlet and outlet ports, respectively, which are located adjacent one another on the pump housing in parallel, fixed orientation. Handling the fluid conduit individually is labor intensive. Bundling the conduits together with a rigid connecting plate saves on labor, but presents difficulties if the center-to-center spacing of the bundled conduits does not match up precisely with the center-to-center spacing of the fluid ports in which they are installed. Misalignment of the conduits relative to the ports can place unwanted stress on the port seals and could present fluid leakage problems.
A conduit fluid sealing system constructed according to the invention overcomes or greatly minimizes the foregoing deficiencies of the known prior systems.
A fluid sealing system constructed according to the invention includes a fluid housing having at least the fluid ports disposed in laterally fixed, parallel relation to one another. Within each port there is disposed a fluid seal. At least two associated fluid conduits are provided having distal ends which are extendible into their associated fluid ports into sealing engagement with the fluid seals. A retaining plate supports the conduits in laterally spaced, parallel relationship with one another in such a way that the conduits can move relative to one another in the lateral direction to enable the conduits to be installed together as a bundled unit while enabling for adjustment in the lateral spacing of the conduits during installation to achieve matched alignment between the spacing of the conduits and the fixed spacing of the fluid ports.
The invention thus has the advantage of simplifying the installation and reducing the labor and cost of connecting the fluid conduits by bundling them together as a unit while enabling relative lateral movement of the conduits for precise center-to-center alignment with the fixed positions of the fluid ports.
Another advantage of the present system is that the precise alignment insures proper alignment with the port seals and thus improves the overall sealing performance of the system.
The invention further provides improvements in the port seals to achieve improved sealing performance. Rupturable membrane seals are provided which, according to one aspect of the invention, incorporate a generally C-shaped pre-weakened tear seam defining a tear flap and hinge region. The hinge region is formed with a reinforcement rib to better control tearing of the membrane. According to another aspect of the invention, the membrane has tapered walls which extend axially inwardly of the port and converge at a tear seam, allowing for a sealing rib of the seal ahead of the tear seam to engage and seal about the conduit before rupturing of the seam, eliminating possible fluid leakage from the ports.